广西钦州湾海岸带孢粉组合和沉积环境演变  

POLLEN ASSEMBLAGE AND SEDIMENTARY ENVIRONMENT EVOLUTION IN THE COASTAL ZONE IN QINZHOU BAY,GUANGXI PROVINCE

作　　者：李贞[1] 李珍[1] 张卫国[1] 李杰[2] 孟宪伟[3] 刘乐军[3] 李朝新[3] 

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200062 [2]云南省环境科学研究院,昆明650034 [3]国家海洋局第一海洋研究所,青岛266061

出　　处：《第四纪研究》2010年第3期598-608,共11页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:4060601 8和40971035);广西908专项项目(批准号:GX908-01-02)资助

摘　　要：对广两钦州湾海岸滩涂的4个钻孔的沉积物进行孢粉分析,结合^(210)Pb法测得沉积速率,讨论了该地区大约150年来的沉积环境演变规律。钦州湾地区具有19世纪中-末叶较现在偏凉的区域性气候;20世纪初期西海岸沉积物中红树林花粉Rhizophora和Aegiceras锐减,反映出红树林滩衰退的特征;60年代和70年代,钦州湾西海岸线明显向内陆迁移,高潮滩环境向低潮滩演化;而80年代始,东海岸线由于钦江流域来沙的迅速堆积,沉积速率较高,岸线向海推移明显,沉积物中木本植物花粉和禾本科均有所增加,这和围垦修堤的人类活动加速了低潮滩向高潮滩演化有关。钦州湾总体表现出西向扩张,东向缩减的趋势。The sedimentary environment evolution of the tidal zone in Qinzhou Bay,Guangxi Province during the last 150 years was studied by pollen and grain size analyses for 4 sediment cores longer than !m from 4 boreholes and in combination with sedimentation rates measured with the ^210Pb method. Sediments from cores of boreholes LMOI （ 21 °45′ 13″N, 108 °32′50″E ） and Q32 （ 21°50′45″N, 108 °35 ′31 ″E ） are dominated by silty sand, whereas sediments from cores of boreholes Q24 （ 21 °52′11 ″N, 108°30′22″E ） and Q37 （ 21 °48 ′34″N, 108°30′18″E ） by sandy silt. The sedimentation rate was determined to be 0.61cm/a for borehole LM01 core,0.25cm/a for borehole Q24 core,1.68 cm/a for borehole Q32 core, and 0.63cm/a for borehole Q37 core; the deposition time determined to be about 1846 AD for the bottom of borehole LM01 core,about 1727 AD for the bottom of borehole Q24 core,about 1956 AD for the bottom of borehole Q32 core,and about 1864 AD for the bottom of borehole Q37 core. In general,the high content of temperate pollen including Fagus in borehole LM01 core and Fagus, Aceraceae, and Juglandaceae in borehole Q24 core indicates that the regional climate in the 19^th century was cooler than that at present. In the early 20^th century,a rapid decrease of mangrove pollen Rhizophora and Aegiceras reflected a decline of mangrove beaches in the west coastal of Qinzhou Bay. In the 1960s and 1970s,the shoreline in the western area migrated landward and the high tidal flat evolved into the low tidal flat, which can be evidenced by the increased content of the fern spores and Pinus pollen in boreholes LM01, Q24 and Q37 cores. From the 1980s on, accompanied with high accumulation rates, the shoreline in the eastern area migrated rapidly seaward because of much more materials transported by the Qinjiang River,which can be evidenced by more arboreal pollen and Poaceae pollen. Human activities such as reclamation and embankment have also accelerated the evolution from the low tidal fla

关 键 词：钦州湾 孢粉组合 沉积环境 ^210PB 粒度 

分 类 号：Q913.84[天文地球—古生物学与地层学] X14[生物学—古生物学]